Forty years ago, Dr. Jack Wennberg and colleagues at Dartmouth Medical School published the first of a series of groundbreaking studies of medical resource utilization and practice variations that would eventually become the Dartmouth Atlas of Health Care. They found huge variations in how often elective surgeries such as tonsillectomies were performed in different parts of New Hampshire, even in neighboring cities and counties. These geographical variations could not be explained by differences in the demographics or health of patient populations, and outcomes in areas with more surgeries per capita were no better, and sometimes worse, than in those with fewer surgeries. Subsequent studies identified similar unwarranted variations in many other procedures and treatments paid for by Medicare, leading to a consensus among policymakers that the U.S. health system spends hundreds of billions of dollars each year on medical care (termed “waste”) that has no health benefits and often harms patients.

To my profession’s credit, physician organizations are finally taking unprecedented steps to confront the problem of waste in medicine. The American Board of Internal Medicine Foundation’s Choosing Wisely campaign, which asks each partnering group to identify 5 commonly performed tests or treatments that should be questioned by physicians and patients, has signed up more than 50 specialty organizations to date, with more to come in the next several months. Next week, screening and diagnostic experts from all over the world will gather at Dartmouth to discuss strategies for Preventing Overdiagnosis, a problem that is largely created by physicians looking too hard for diseases with imperfect tests that lead to many false positive results and more invasive procedures, such as biopsies. (Even if the tests themselves were perfect, they are often performed in patients who could not possibly benefit from the results, such as patients with terminal cancer.)

But if the problems of medical waste and overdiagnosis are familiar to doctors, most patients are still in the dark about the basics. For example, how is someone without medical training expected to know the difference between a test that might help and a test that is potentially harmful (and, since many tests meet both criteria, weigh the benefits and harms and make a decision that accurately reflects his or her preferences)? When should you suspect that your doctor is testing or treating too aggressively and ask for a second opinion? How do you know if you may have been overdiagnosed? What components of a complete physical are supported by good evidence, rather than simply relics of medical tradition? Does a physical really need to be done annually, or at all?

These are the sorts of questions that I plan to answer to the best of my ability in Conservative Medicine. Now is the right time for this book, but in many ways, the topics of this book are timeless.